1_IP网络的现状和发展

计算机网络技术的历史和新进展主要内容•Internet的发展和成功经验•高速计算机网络技术发展的现状•国际高速计算机网络技术研究计划•中国计算机网络技术研究计划•高速计算机网络技术发展战略•机会和挑战并存，挑战大于机会WhatisaNetwork?(fromendsystempointofview)•Networkoffersaservice:moveinformation–bird,fire,messenger,truck,telegraph,telephone,Internet…–anotherexample,transportationservice:moveobjects•horse,train,truck,airplane...•Whatdistinguishdifferenttypesofnetworks?–Theservicestheyprovide•Whatdistinguishtheservices?–latency–bandwidth–lossrate–numberofendsystems–serviceinterface(howtoinvoke?)–otherdetails•reliability,unicastvs.multicast,real-time,messagevs.byte...WhatisaNetwork?InfrastructureCentricView•Electronsandphotonsascommunicationmedium•Links:fiber,copper,satellite,…•Switches:mechanical/electronic/optical,crossbar/Banyan•Protocols:TCP/IP,ATM,MPLS,SONET,Ethernet,PPP,X.25,FrameRelay,AppleTalk,IPX,SNA•Functionalities:routing,errorcontrol,congestioncontrol,QualityofService(QoS)•Applications:FTP,WEB,Xwindows,...TypesofNetworks•Geographicaldistance–LocalAreaNetworks(LAN):Ethernet,Tokenring,FDDI–MetropolitanAreaNetworks(MAN):DQDB,SMDS–WideAreaNetworks(WAN):X.25,ATM,framerelay•Informationtype–datanetworksvs.telecommunicationnetworks•Applicationtype–specialpurposenetworks:airlinereservationnetwork,bankingnetwork,creditcardnetwork,telephony–generalpurposenetwork:InternetTypesofNetworks•Righttouse–private:enterprisenetworks–public:telephonynetwork,Internet•Ownershipofprotocols–proprietary:SNA–open:IP•Technologies–terrestrialvs.satellite–wiredvs.wireless•Protocols–IP,AppleTalk,SNATheInternet•Globalscale,generalpurpose,heterogeneous-technologies,public,computernetwork•InternetProtocol–openstandard:InternetEngineeringTaskForce(IETF)asstandardbody–technicalbasisforothertypesofnetworks•Intranet:enterpriseIPnetwork•DevelopedbytheresearchcommunityHistoryoftheInternet•70’s:startedasaresearchproject,56kbps,100computers•80-83:ARPANETandMILNETsplit,•85-86:NSFbuildsNSFNETasbackbone,links6Supercomputercenters,1.5Mbps,10,000computers•87-90:linkregionalnetworks,NSI(NASA),ESNet(DOE),Bartnet,100,000computers•90-92:NSFNETmovesto45Mbps,16mid-levelnetworks•94:NSFbackbonedismantled,multipleprivatebackbones•Today:backbonesrunat2.4Gbps,10smillionscomputersin150countriesGrowthoftheInternet•NumberofHostsontheInternet:Aug.1981213Oct.19841,024Dec.198728,174Oct.1990313,000Oct.19932,056,000Apr.19955,706,000Jul.199719,540,000Jul.200093,047,7851101001000100001000001000000100000001000000001981年1986年1991年1996年RecentGrowth(1991-2000)WhoisWhoontheInternet?•InternetEngineeringTaskForce(IETF):TheIETFistheprotocolengineeringanddevelopmentarmoftheInternet.Subdividedintomanyworkinggroups,whichspecifyRequestForCommentsorRFCs.•IRTF(InternetResearchTaskForce):TheInternetResearchTaskForceisacomposedofanumberoffocused,long-termandsmallResearchGroups.•InternetArchitectureBoard(IAB):TheIABisresponsiblefordefiningtheoverallarchitectureoftheInternet,providingguidanceandbroaddirectiontotheIETF.•TheInternetEngineeringSteeringGroup(IESG):TheIESGisresponsiblefortechnicalmanagementofIETFactivitiesandtheInternetstandardsprocess.Standards.ComposedoftheAreaDirectorsoftheIETFworkinggroups.InternetStandardizationProcess•AllstandardsoftheInternetarepublishedasRFC(RequestforComments).ButnotallRFCsareInternetStandards!–available:•Atypical(butnotonly)wayofstandardizationis:–InternetDrafts–RFC–ProposedStandard–DraftStandard(requires2workingimplementation)–InternetStandard(declaredbyIAB)•DavidClark,MIT,1992:Wereject:kings,presidents,andvoting.Webelievein:roughconsensusandrunningcode.”ServicesProvidedbytheInternet•Sharedaccesstocomputingresources–telnet(1970’s)•Sharedaccesstodata/files–FTP,NFS(1980’s)•Communicationmediumoverwhichpeopleinteract–email(1980’s),on-linechatrooms,instantmessaging(1990’s)–audio,video(1990’s)•replacingtelephonenetwork?•Amediumforinformationdissemination–USENET(1980’s)–(1990’s)•replacingnewspaper,magazine?–audio,video(1990’s)•replacingradio,CD,TV?Today’sVision•Everythingisdigital:voice,video,music,pictures,liveevents•Everythingison-line:bankstatement,medicalrecord,books,airlineschedule,weather,highwaytraffic,toaster,refrigerator…•Everyoneisconnected:doctor,teacher,broker,mother,son,friends,enemiesWhatisNext?•Electroniccommerce–virtualenterprise•Internetentertainment–interactivesitcom•Worldasasmallvillage–communityorganizedaccordingtointerests–enhancedunderstandingamongdiversegroups•Electronicdemocracy–littlepeoplecanvoicetheiropinionstothewholeworld–bridgethegapbetweeninformationhavesandhaveno’s•Electronicterrorism–hackercanbringthewholeworldtoitskneeIndustrialPlayers•Telephonecompanies–ownlong-haulandaccesscommunicationlinks,customers•Cablecompanies–ownaccesslinks•Wireless/Satellitecompanies–alternativecommunicationlinks•Utilitycompanies:power,water,railway–ownrightofwaytolaydownmorewires•Mediumcompanies–owncontent•InternetServiceProviders•Equipmentcompanies–switches/routers,chips,optics,computers•SoftwarecompaniesCommercialInternetafter1994NSFNetworkRegionalISPAmericaOnLineIBMBartnetCampusNetworkJoe'sCompanyStanfordXeroxParcBerkele